True. Peanut butter's not healthy for them, though, is it?Why go through all that trouble? You aren't feeding children. If you want to give them peanut butter, give them peanut butter. Honey, baking powder and salt probably wouldn't be the best idea.
Brewer's yeast is the way to go.
It may have protein but as a vegetative source, it will be incomplete in essential amino acids.
Hence the name, duckweed.
If the fish are herbivorous, they'll likely eat it. If they're carnivorous, like cichlids, they won't. If they're omnivorous, they may. If they're micro-predators, likely not.
Good to know about duckweed. I suppose an incomplete food like that would decrease the amount of eggs I get?